Predictive anthropometric measurements, associated factors, outcomes, and genetic factors involved in maternal overweight and obesity in HIV-infected and HIV-uninfected black South African pregnant women.

Abstract

Background: The proportion of overweight and obese people living with human immunodeficiency virus (HIV) infection have increased globally and are both epidemics that are endemic to countries like South Africa. Targeting these two epidemics in pregnant women, need to be a priority in maternal health research, with the findings from these studies aimed to eventually translate into improving maternal health outcomes. Aims and objectives: This study aimed to evaluate the anthropometric differences, factors, outcomes, and epigenetic factors involved in pregnant black South African pregnant women with a body mass index (BMI) ≥25.0 kg/m2 in comparison to those with a BMI <25 kg/m2. The specific study objectives were to: (i) investigate the relationship between maternal BMI and maternal anthropometric measurements among black South African pregnant women; (ii) identify what measurement cut-offs accurately predict each nutritional status group; (iii) investigated the anthropometric differences between pregnant women living with and without HIV; (iv) investigate the differences between the pregnant women with a BMI of ≥ 25.0 kg/m2 compared to those with a BMI <25.0 kg/m2; (v) investigate the factors associated with overweight and obesity in both HIV-infected and HIV-uninfected pregnant South African women; (vi) investigate the maternal health outcomes associated with overweight and obesity in both HIV-infected and HIV-uninfected pregnant South African women; and (vii) investigate whether maternal BMI and HIV status had an effect on the mRNA expression of adiponectin (ADIPOQ), leptin (LEP), leptin receptor (LEPR), fat mass and obesity-associated (FTO), and ghrelin (GHRL) in visceral adipose tissue (VAT) and in whole blood (WB) obtained from pregnant black South African women. Method: A cross-sectional study design was employed. Sample selection was conducted at Prince Mshiyeni Memorial Regional Hospital, which is situated in Umlazi within the eThekweni municipality, KwaZulu-Natal, South Africa. The catchment area for the hospital includes both rural and urban geographical areas. Pregnant women admitted to the labour ward were approached to participate in this study. The inclusion criteria for this study were as follows: (1) ≥ 18 years of age; (2) pregnant females; (3) black South African citizen; (4) clinically stable; (5) able to stand without assistance; (6) given verbal and written consent to participate in the study; and (7) gave consent to obtain a VAT sample during their c-section operation. The participants were categorized x according to BMI (kg/m2) into two groups: (1) overweight/obese pregnant women (≥25kg/m2); and (2) non-overweight/non-obese pregnant women (<25kg/m2). A total of 458 pregnant women were approached to participate in the study, but 245 subjects met the inclusion criteria and of these 45 declined to participate. Hence, a total of 200 subjects met all the inclusion criteria, but of these participants only 79 subjects were able to provide a VAT sample. The statistical tests that were applied included: (i) Fisher’s exact test and the χ 2 test; (ii) Pearson correlation coefficient; (iii) the Spearman’s rank-order correlation coefficient; (iv) the Mann Whitney t-test; (v) one-way ANOVA; (vi) area under the curve of the receiver operator characteristic curves to determine the cut-off values; and (v) simple logistic regression was performed to select the variables for multiple logistic regression analysis, and only variables with a p-value <0.05. A p-value of <0.05 was considered statistically significant. Results: Maternal age was significantly positively associated with changes in maternal anthropometric measurements. Maternal BMI was significantly positively correlated with other maternal anthropometric measurements including mid upper arm circumference (MUAC) (left and right), tricep skinfold (TSF) (right), subscapular skinfold (SSF) (right), mid arm muscle circumference (MAMC) (right), wrist circumference (WC) (right), but significantly negatively correlated with frame size. The anthropometric methods that were accurate for assessing obesity in pregnancy included TSF (right) (cut-off of ≥20.75 mm), SSF (right) (cut-off of ≥21.75 mm), MAMC (right) (cut-off of ≥25.23 cm), and WC (right) (cut-off of ≥16.25cm). Also, SSF (right) (cut-off of ≥15.75mm) and MAMC (right) (cut-off of ≥23.35cm) could be used to assess for overweight nutritional status. Lastly, frame size could be used to assess for underweight (cut-off of ≥10.05) and normal (cut-off of ≥9.95) nutritional status. The HIV-infected pregnant women did not differ anthropometrically to the HIV-uninfected pregnant women. The demographic characteristics, food frequency intake, physical activity and lifestyle characteristics were not significantly different between the participants with a BMI of ≥ 25.0 kg/m2 compared to those with a BMI of <25 kg/m2. The dietary pattern of the overweight/obese participants showed that there was a higher intake of saturated fat, higher in salt, higher in sugar, higher in animal protein, lower in dairy, higher in legumes, higher in starch, higher in vegetables, and had a similar intake of fruit in comparison to the non-overweight/non-obese participants. Also, maternal age was significantly different between those with a BMI ≥25 kg/m2 compared to those with a BMI <25 kg/m2, where the overweight and obese participants were significantly older (p=0.0173). Multiple logistic

regression analysis showed that maternal age (OR:1.061; 95%CI 1.008-1.117; p=0.023) and gestational age (OR:1.121; 95%CI 1.005-1.251; p=0.041) were significantly associated with maternal overweight and obesity in both HIV-infected and HIV-uninfected pregnant women. For maternal health outcomes, multiple logistic regression analysis showed that HPT disorders (OR:0.273; 95%CI 0.124-0.601; p=0.001) and anaemia (OR:2.420; 95%CI 1.283-4.563; p=0.006) were significantly associated with maternal overweight and obesity in both HIV-infected and HIVuninfected pregnant women. The overweight and obese HIV-infected pregnant women (OR:0.233; 95% CI 0.075-0.717; p=0.011) had increased odds for developing HPT disorders compared to HIV-uninfected overweight and obese pregnant women (OR:0.471; 95% CI 0.172-1.291; p=0.143). It was identified that there were statistically significant differences for ADIPOQ (p <0.001), LEP (p=0.0105) and LEPR (p=0.0220) where mRNA expression was greater in the VAT compared to WB. The mRNA expression of FTO was similar in VAT and WB (p=0.4039). There were no significant differences in mRNA expression for ADIPOQ, LEP, LEPR and FTO between all the BMI and HIV status groups. However, there were patterns identified that allude to BMI, HIV, and the combination of BMI and HIV which showed that there was an effect on the mRNA expression of ADIPOQ, LEP, LEPR and FTO in the pregnant women. The pregnant women with a BMI ≥25.0 kg/m2 showed a downregulatory pattern for ADIPOQ, LEP, LEPR and FTO in VAT and WB. The HIV-infected pregnant women showed a downregulatory pattern for ADIPOQ, LEP, LEPR and FTO in VAT and WB. The HIV-infected pregnant women with a BMI ≥25.0kg/m2 had the lowest mRNA expression for ADIPOQ, LEP, LEPR and FTO in VAT and WB. The mRNA expression of GHRL in the VAT and WB samples from the pregnant women was undetectable. Conclusion: Maternal nutritional status can be accurately predicted by using surrogate maternal anthropometric measurements such as MUAC, TSF, SSF, MAMC, WC, and frame size. Pregnant women living with HIV do not differ anthropometrically to pregnant women living without HIV. Maternal overweight and obesity in both HIV-infected and HIV-uninfected pregnant black South African women was significantly associated with maternal age, gestational age, HPT disorders and anaemia. Maternal overweight/obesity decreased the odds for anaemia during pregnancy but increased the odds for the development of HPT disorders during pregnancy, especially in the HIVinfected pregnant women. Pregnant black South African women presenting with overweight/obesity and being HIV-infected showed to have the worst downregulatory effect on mRNA expression of ADIPOQ, LEP, LEPR, and FTO. The downregulation of these genes may

result in the dysregulation of metabolic pathways that usually control weight gain during pregnancy.